Agriculture and Climate Change: Exploiting the nexus within

  A ‘nexus’ refers to a relationship or connection between people or things often and this connection usually is a complicated one. We all of us have heard about the word nexus; but most of us may not have read the term being used in agriculture. When I talk of the nexus between agriculture and climate change, I simply mean to convey the deep rooted connection that exists between agriculture and the climate change. Climate change has both direct and indirect effects on agricultural productivity including changing rainfall patterns, drought, flooding and the geographical redistribution of pests and diseases. Actually, agriculture is one sector which is a cause for climate change as well as gets adversely affected by the climate change.

Climate Change

The National Aeronautics and Space Administration (NASA) define Climate change as ‘a broad range of global phenomenan created predominantly by burning fossil fuels, which add heat-trapping gases to Earth’s atmosphere. These phenomenan includes the increased température trends described by global warming, but also encompass changes such as sea-level rise; ice mass loss in Greenland, Antarctica, the Arctic and mountain glaciers worldwide; shifts in flower/plant blooming; and extreme weather évents.’

Climate Change vs. Global Warming 

According to the US Geological Survey, Global warming is just one aspect of Climate Change. Infact they say that Global Warming refers to the rise in global températures mainly due to the increasing concentrations of green house gases in the atmosphere. On the other hand, climate change refers to the increasing changes in the measures of climate over a long period of time including precipitation, temperature, and wind patterns.

The Nexus

Agriculture as already told has a deep connection with climate change. It is a sector which contributes to the climate change as well as is affected by the climate change. The sector contributes to the climate change mainly through emission of green house gases like methane, carbon dioxide, nitrous oxide. Methane gets produced during the microbial decomposition of organic matter under anaerobic conditions. Rice fields when kept submerged in water become potential source of methane production. Livestock is another potential source of methane emission. The process of enteric fermentation in the ruminants also liberates methane in the atmosphere. Burning of crop residues as is seen in states of Punjab and Haryana is also a source of methane emission besides a source of pollution of the atmosphere. Similarly carbon dioxide, another potent green house gas results from burning of fuel in machinery during various agricultural operations, burning of crop residues and biological decomposition of soil organic matter. The Nitrous Oxide gets released in the atmosphere by the use of nitrogenous fertilizers. The country’s contribution is only 5 per cent of the total global emission of 55 billion tonnes of CO2 equivalent. Of this 55 billion, agriculture contributes 11-12 per cent of which share of Indian agriculture is just 1 per cent. The highest contributor to green house gas emission in the country is the energy sector (65%), followed by agriculture (18%) and Industry (16%). Indian agriculture sector including crop and animal husbandry emits about 420 Mt of CO2 equivalents. Since 1970, the GHG emission from agriculture in India has increased by about 80 per cent and this is attributed to the increased use of chemical fertilizers and other inputs in agriculture.

It is expected that by the year 2030, the green house gas emissions from agriculture will be almost 60 per cent higher than in 1990. The largest increase will be in the form of N2O (75%) emissions from soil as use of fertilizers increases. Emission of CH4 from other agricultural sources will also grow greatly. Given the increase in population in the coming decades and subsequent increase in requirement of food grain production, apprehension is that the green house gas emissions will increase due to increased use of chemical fertilizers. The projected trends of Green House Gas emission from the agriculture sector in India indicate that under the business as usual scenario, the emission will increase by 17% by 2030 compared to that in 2010. The deep nexus between climate change and agriculture has also hastened the biotic stresses including boosting up the population of insect/pest and incidence of disease, increased weed growth, decline in population of beneficial soil microbes, threatening of pollinators and boosting up abiotic stresses including harsh drought/floods and water logging, extremisms in temperature, salinity/alkalinity, abrupt rainfall pattern that ultimately affect the plant in multiple ways. 

In 2021, extreme weather events wrought yet another distressing year for Indian farmers. Cyclone Tauktae and Yaas wreaked havoc in several states in the first few months especially in Odisha, West Bengal and Karnataka where lives and livelihoods were affected beyond redemption. In July, floods in Maharashtra damaged standing crops. This was followed by a 24 per cent nationwide rain deficit in August and 35 per cent excess rain in September. In October, heavy rains destroyed harvest-ready crops in many districts of Kerala. In India, around 36 million hectare agricultural area was affected due to hydro-meteorological calamities, including heavy rain and floods. This has led to repeated losses for farmers, especially small and marginal ones who comprise over 85 per cent of the total number of farmers in the country. Although, there is no available national data on the monetary loss owing to damage of crops in 2021 but a rough estimate puts the monetary loss to the tune of Rs 29,939 crore loss for the farmers. The cumulative effect of climate change also threatens our ability to ensure global food security, eradicate poverty and achieve sustainable development. The adoption of various climate smart agriculture technologies can help us to mitigate the adverse effects of climate change. 

Climate Smart Agriculture

Climate Smart Agriculture (CSA) is a pathway towards development and food security built on three pillars: increasing productivity and incomes, enhancing resilience of livelihoods and ecosystems and reducing and removing greenhouse gas emissions from the atmosphere. Climate smart agricultural practices considerably help in reducing the green house gas emissions and conservation of natural resources. We have to adopt agronomic practices minimum or no till agriculture with crop rotations that reduces water requirements by up to 30 per cent. Sowing across the slope reduces the erosion of soil and subsequent removal of nutrients from the soil thereby maintaining the fertility of the soil. Sowing in lines using seed cum ferti-drill or maize planter reduces the seed rate per hectare, maintains optimum plant to plant distance and reduces the chance of lodging during maturity. 

Farmer due to their ignorance often do not use recommended dose of fertilizers. They often indulge in overdose of chemical fertilizers which result in the increased emission of greenhouse gases. They should be made aware of the right combination and appropriate dose of fertilizers. Bunding is done for control of soil erosion and maintaining soil moisture. Bunding is of various types like block bunding, compartmental bunding and contour bunding. The sloping sides can be planted with grass and trees. Mulching is another simple and one beneficial practice for conserving soil moisture. It is protective layer of the material spread on the top of soil. Soil can be covered by straw, peat, dust, plastic sheets or by maintaining a vegetative cover. Mulching offers several advantages such as conservation of soil moisture, prevention of growth of unwanted plants, maintains an even soil temperature and reduces compaction after heavy rains. The use of local resources like the cow dung, the litter and the urine and other waste materials can be used successfully for preparing compost which can be used as substitute for chemical fertilizers thereby reducing the farmers cost of cultivation besides providing fertility of the soil and maintaining the soil health. Technologies like Direct Seeded Rice (DSR) and System of Rice Intensification (SRI) that makes the least use of water should be promoted and adopted.  

Keeping in mind the scarcity of water can be harvested in pond like structures. The water from these ponds can be used for life saving irrigation to different crops. Roof top harvesting can also be practiced. Rain water can be collected in the roof tops. Drip Irrigation is a water saving technology. Protected cultivation in poly house can be used successfully in high altitude areas for vegetable cultivation throughout the year especially for small holders in which multitier cultivation is possible. The government is also promoting ‘Natural Farming’ aimed at promoting traditional indigenous practices which reduces externally purchased inputs. It is largely based on on-farm biomass recycling with major stress on biomass mulching, use of on-farm cow dung-urine formulations; periodic soil aeration and exclusion of all synthetic chemical inputs. Several studies have reported the effectiveness of natural farming in terms of increase in production, sustainability, saving of water use, improvement in soil health and farmland ecosystem. It is considered as a cost- effective farming practices with scope for raising employment and rural development too.

(Dr. Parveen Kumar is a Faculty at SKUAST-K; can be reached at pkumar6674@gmail.com)